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A simple Kubernetes client-go application that creates and patches imagePullSecrets to service accounts in all Kubernetes namespaces to allow cluster-wide authenticated access to private container registry.

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imagepullsecret-patcher

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A simple Kubernetes client-go application that creates and patches imagePullSecrets to service accounts in all Kubernetes namespaces to allow cluster-wide authenticated access to private container registry.

screenshot

A blog post: https://medium.com/titansoft-engineering/kubernetes-cluster-wide-access-to-private-container-registry-with-imagepullsecret-patcher-b8b8fb79f7e5

Installation and configuration

To install imagepullsecret-patcher, can refer to deploy-example as a quick-start.

Below is a table of available configurations:

Config name ENV Command flag Default value Description
force CONFIG_FORCE -force true overwrite secrets when not match
debug CONFIG_DEBUG -debug false show DEBUG logs
managedonly CONFIG_MANAGEDONLY -managedonly false only modify secrets which were created by imagepullsecret
runonce CONFIG_RUNONCE -runonce false run the update loop once, allowing for cronjob scheduling if desired
serviceaccounts CONFIG_SERVICEACCOUNTS -serviceaccounts "default" comma-separated list of serviceaccounts to patch
all service account CONFIG_ALLSERVICEACCOUNT -allserviceaccount false if true, list and patch all service accounts and the -servicesaccounts argument is ignored
dockerconfigjson CONFIG_DOCKERCONFIGJSON -dockerconfigjson "" json credential for authenicating container registry
dockerconfigjsonpath CONFIG_DOCKERCONFIGJSONPATH -dockerconfigjsonpath "" path for of mounted json credentials for dynamic secret management
secret name CONFIG_SECRETNAME -secretname "image-pull-secret" name of managed secrets
excluded namespaces CONFIG_EXCLUDED_NAMESPACES -excluded-namespaces "" comma-separated namespaces excluded from processing
loop duration CONFIG_LOOP_DURATION -loop-duration 10 seconds duration string which defines how often namespaces are checked, see https://golang.org/pkg/time/#ParseDuration for more examples

And here are the annotations available:

Annotation Object Description
k8s.titansoft.com/imagepullsecret-patcher-exclude namespace If a namespace is set this annotation with "true", it will be excluded from processing by imagepullsecret-patcher.

Providing credentials

You can provide the authentication credentials for imagepullsecret to populate across namespaces in a couple of ways.

You can provide a raw secret as an environment variable, or better yet, by mounting a volume into the container. Mounted secrets can be dynamically updated and are more secure. Please see the relevant docs for more information https://kubernetes.io/docs/concepts/configuration/secret/

Why

To deploy private images to Kubernetes, we need to provide the credential to the private docker registries in either

With the second approach, a Kubernetes cluster admin configures the default service accounts in each namespace, and a Pod deployed by developers automatically inherits the image-pull-secret from the default service account in Pod's namespace.

This is done manually by following command for each Kubernetes namespace.

kubectl create secret docker-registry image-pull-secret \
  -n <your-namespace> \
  --docker-server=<your-registry-server> \
  --docker-username=<your-name> \
  --docker-password=<your-pword> \
  --docker-email=<your-email>

kubectl patch serviceaccount default \
  -p "{\"imagePullSecrets\": [{\"name\": \"image-pull-secret\"}]}" \
  -n <your-namespace>

And it could be automated with a simple program like imagepullsecret-patcher.

Contribute

Development Environment

  • Go 1.13